Automatic transmission



Dec. 10, 1957 Filed Oot. 16. 1950 c. R. ROCHE' 2,815,684

AUTOMATIC TRANSMISSION 6 Sheets-Sheet 1 Dec. 10, 1957 C, R, ROCHE2,815,684

AUTOMATIC TRANSMISSION Filed Oct. 16. 1950 6 Sheets-Sheet 2 ,B 4 LBJNVENTOR.

ML M@ Dec. l0, 1957 c. R. ROCHE 2,315,634

AUTOMATIC TRANSMISSION Filed out. 1s. 195o e sheets-sheet s I N V ENTOR. 5'/ 7210/7 )7 Fac/5e.

M, 2295 yu Dec. l0, 1957 c. R. ROCHE 2,815,684

AUTOMATIC TRANSMISSION Filed Oct. 16. 1950 6 Sheets-Sheet 4 Dec. 10,1957 C, R, rROCHE 2,815,684

AUTOMATIC TRANSMISSION IN VEN TOR.

,7 TraFA/fy DEC. 10, Q R ROCHE AUTOMATIC TRANSMISSION G Sheets-Sheet 6Filed Oct. 16. 1950 www.

I N V EN TUR. {Z/far? 77, oce.

Hrw/mln@ United States Patjfnt O AUTOMATIC TRANSMISSION Clifton R.Roche, Los Angeles, Calif.

Application October 16, 1950, Serial No. 190,384

37 Claims. (Cl. 74-645) The present invention relates to automatictransmissions, particularly for automotive vehicles.

My objects in the development of the present invention may be summarizedas comprising the provision of an automatic transmission having highperformance characteristics, but which is less expensive to construct,more compact, and easier to service than other comparable transmissionsof which l am aware.

Among more specific objects of this invention are to provide an improvedhydraulic torque converter having novel and improved cooling means, andimproved lock-out clutch mechanism for the hydraulic torque converter,including a novel blocker synchronizer arrangement; improvedtransmission mechanism incorporating a hydraulic torque converter andtwo geared ratios, designed in such manner that either one or two gearedstarting ratios may be employed (to supplement the increased torquederivable from the hydraulic torque converter); and novel and improvedmeans preventing the frequent shifting into and out of the gearedstarting ratio (or ratios) during low speed driving in traiiic or thelike, where the speed of the vehicle is varied frequently, and oftenquite abruptly, but primarily at low speeds; the elimination of suchunpleasant frequent automatic shifting rendering the operation of thevehicle at such low speeds smoother as well as more economical.

A further object is to provide an improved structural arrangement fortransferring to rigid stationary portions of the casing the forces andreactions applied to brake bands and brake drums employed to regulatethe action of the geared drives. Stili another object is to providenovel, compactly interlitted means for mounting certain of the clutchesand gearing to reduce the over-all dimensions and cost of the assembly.Another object is a novel improved parking lock arranged to rigidly holdthe car against rolling. Another object is to provide means forpreventing dangerously high rotative speeds of any of the operatingparts in event the engine is raced with the parking lock applied.Another object is to provide an improved brake construction includingimproved brake band constructions.

Other objects pertain to the provision of an improved hydrauliccontrolling system for such a transmission, which controlling systemincludes means for automatically varying the effective iluid pressure inthe operative portions of the control system in conformity with thetorque demand upon the transmission mechanism. This eliminates loss ofeiciency due to the expenditure of engine output in the maintenance ofunnecessarily high pressures when not required.

Another object is to provide is a controlling system for a transmissionof the indicated character, which incorporates a lock-out clutch for thehydraulic torque converter, novel means providing a high speed kickdownfrom the high speed drive to a geared drive without releasing the torqueconverter lock-out clutch. This eliminates the lag which occurs uponkickdown in the opera- Patented Dec. 10, 1957 tion of some transmissionsdue to the sudden increase of slip in the torque converter when a geareddrive is suddenly thrown into the line of drive.

Another important object is the provision of improved means for timingthe disengagement of clutches and brake bands which are to be releasedupon the engagement of others which are called upon to take up thetransmission o2" torque.

Still another object is to provide an improved uid supplying meansincluding two fluid supply pumps, one operated by a driving element ofthe transmission and another by a driven element of the transmission,and novel means whereby the fluid is at certain times supplied by one ofsaid pumps, and at other times by the other pump.

A further object is the provision of an improved and simplifiedanticreep system.

The foregoing and other objects which will become apparent uponconsideration of the present disclosure in its entirety are achieved ina transmission -construction which incorporates a hydraulic torqueconverter, two fluid pumps and planetary gearing, the generalarrangement of the planetary gear train and the manner in which thegeared driving ratios are secured being similar to an arrangementdisclosed in my copending application Serial No. 748,382, filed May 16,1947, but the use of overrunning clutches to allow the effective releaseof one ratio when another picks up the drive being dispensed with, andin lieu thereof novel timed operating means and two-way acting clutchesbeing provided. Automatic free-wheeling is thereby eliminated entirelyfrom the mechanical action of the transmission, the release andengagement of the driving ratios being entirely regulated by thehydraulic control system.

ln the drawings:

Figure 1A is a view in substantially diametric vertical longitudinalsection, partly broken away, of the forward portion of an improvedtransmission incorporating my invention, including certain diagrammaticshowings of control components;

Fig. 1B is a similar view of the central or mid portion of thetransmission;

Fig. 1C is a similar view of the rear portion of the transmission;

Fig. 2 is a diagrammatic view of the principal mechanical components ofthe transmission;

Fig. 3 is a cross section taken substantially on the line 3 3 of Fig.1C, and looking in the direction of the arrows;

Fig. 4 is a partly diagramatic cross-sectional view of the brakingmechanism for controlling the reverse drive, taken substantially on theline 4-4 of Fig. 1B;

Fig. 5 is a view similar to Fig. 4 of a braking mechanism forming a partof the means for controlling the forward geared speeds, takensubstantially on the line 5-5 of Fig. 1C;

Fig. 6 is a diagrammatic view of the principal hy draulic components,and certain related mechanical cornponents, of the control system.

Figures 1A, 1B, 1C, 4, 5 and 6 all contain diagrammatic representationsof luid passages. Figures 1A, 1B and 1C can be arranged in alignedrelation from left to right in the order named and with the similarlydesignated vertical broken lines A-A and B-B in registry with oneanother, to aiord a complete sectional drawing of my preferredtransmission, and Fig. 6 can be placed below such assembled figures, andFigs. 4 and 5 can be placed above such assembled Figures 1A, 1B and 1C,with the similarly designated tiuid passages of the several viewspositioned to form continuations of one another, to afford a completediagrammatic showing of the control system in conjunction with relatedmechanical features shown in Figures lA, 1B and 1C.

General arrangement of principal mechanical components Referring firstto the diagrammatic representation of the mechanical components depictedin Fig. 2, an outline description will first be given of the generalarrangement and operation of the principal mechanical features.

The driving shaft of the transmission is indicated at 10, and maycomprise the crankshaft of the engine (a vehicular installation beingpresumed, as previously indicated). The crankshaft drives the pumpmember 12 of a hydraulic torque converter which is generally designated14. The pump member 12 is at the rear, and is connected to the drivingshaft by the casing portion 15, as is common practice. The torqueconverter is indicated as provided with a single reactor portion 16 anda single turbine portion 18. The reactor is connected through anoverrunning brake 21 to a stationary portion 23 of the casing. Theturbine member 18 is rigidly attached to a transmission shaft 20, theforward end of which is piloted in the driving shaft. A positive toothedtype of lock-out clutch 22 is provided for the members 15 and 18 of thehydraulic torque converter.

At its rear end the transmission shaft is rigidly connected to theinternal toothed ring gear 24 of a front planetary gearset which isgenerally designated 25. The output shaft of the transmission` which maybe directly coupled to the propeller shaft of the vehicle, is piloted atits forward end in the rear end of the transmission shaft. The threeshafts 10, 20 and 30 are axially aligned. The carrier 26 of the frontplanetary gearset is secured to a hollow shaft 28 journaled on theforward end of the out put shaft 30. The front planet gears 32 mesh witha sun gear 33 fast upon another hollow shaft portion 34 which surroundsthe shaft 28. Attached to rotate with the carrier 26 and extendingradially outwardly behind the front planetary gearset 25, and thenceforwardly around the outside of such gearset, is a brake drum 35. Abrake band 36 is engageable with such drum to control the operation ofthe reverse gear drive. The brake drum may also be supported by a hubportion l92 at its forward end journaled on a xed casing portion, aswill presently be brought out in greater detail.

A second or rear planetary gearset is provided, generally designated 40,and which includes an internal toothed ring gear 42. to which the hollowshaft 28 is rigidly connected, a carrier 44 which is rigidly connectedto the output shaft 30, and a sun gear 45 which is fast with respect toa set of clutch plates 46.

A hollow drum 5@ spacedly surrounds the rear gearset and contains twofriction disk-type hydraulically operable clutches. The drum is rigidlyattached to the hollow shaft 34 by a web 52 and is provided with acentral partitioning web 54, forwardly of which is a disk clutchgenerally designated 55, while to the rear of the partition is anotherdisk clutch assembly generally designated 56. Clutch includes platemeans as Slt keyed to drum Si) and adapted to coact with friction disksas which are fast with respect to the internal toothed gear 42. Thisclutch is adapted to be engaged and released by piston means 62. In theclutch 56 are plate means as 64 keyed to drum 50 and adapted to coactwith the plates 46, engagement and release of this clutch being effectedby means of a piston 65. Rigidly secured with respect t0 clutch plates46 and rear sun gear 45 is a brake drum portion 66. A brake band 68 isengageable with the drum 66 to control the operation of the forwardgeared drives of the transmission.

The periphery of the drum 35 is also provided with a series of apertures198 with which a holding dog 200 is engageable to form a parking lock,which will presently be more fully described.

Operation of principal mechanical components A low speedgeared-hydraulic forward drive is secur- `able by engaging the brakeband 68 and the clutch 56 and leaving the other clutches and brakesreleased. This will le seen to hold both sun gears 33 and 45 stationary.When the engine is speeded up sufficiently to transmit enough torque tomove the vehicle, the turbine member 18 turns the ring gear 24forwardly, rolling the planet gears 32 on the sun gear 33 and therebyturning the rear internal gear 42 forwardly, the rear planet gears beingrolled upon the sun gear 45 and turning the carrier 44 and output shaft30.

An intermediate speed geared-hydraulic drive is obtained by engagingonly the clutch 5S and band 68. Clutch 55 then locks up the frontgearset, since the carrier 26 and sun gear 33 are prevented fromrotating with relation to one another. The rear sun gear 4S is held bythe band 68, and reduction is afforded only by the rear gearset.

A direct drive through the gearing is achieved by disengaging the band68 and engaging only the clutches 55 and S6, which locks up bothgearsets, so that they turn as a unit with the transmission shaft 20.Preferably also the clutch 22 is engaged to lock-out the hydraulictorque converter.

Reverse drive `through the gearing is obtained by engaging only thebrake band 36 and clutch 56. Under such conditions, the front carrier 26and rear ring gear 42 are held stationary. Rotation of the front planetgears 32 by the front ring gear 24 turns the front sun gear 33backwardly. The drive is transmitted from the front sun gear throughshaft 34, web 52, drum 50 and clutch 56 to rear sun gear 45 which rollsthe rear planet gears 48 rearwardly on the internal gear 42, carryingthe carrier 44 and propeller shaft 30 rearwardly at reduced speed.

Engagement of clutch 22 locks out the hydaulic torque converter, and Ipreferably engage this clutch when driving at ordinary road speeds, andalso maintain engagement of this clutch when the transmission is shifteddown to the intermediate ratio at relatively high speeds by the kickdownshift means, as will presently appear in connection with the discussionof the control aspects of the transmission.

In neutral, with the engine running, clutch 56 is engaged and the otherclutches and brakes are disengaged. By reason of the engagement of theclutch 56 when the transmission is in neutral, `the danger of damagingthe bearings of the front planet gears in event the engine is raced withthe transmission in neutral is eliminated. lf the clutch 56 were notengaged, and the engine were raced in neutral, and if the friction inthe rear planetary gearset should be higher than in the front set, sothat all of the rotation took place in the front gearset, the frontplanet gears might be spun at very high speeds and darnage to the frontplanet gear bearings could result. By reason of the engagement of theclutch 56, however, the rotation of the engine with the transmission inneutral tends to turn the rear sun gear 45 rearwardly and the rearinternal toothed gear 42 forwardly. The rear planet gears 48 turn ontheir spindles, since the rear carrier is held stationary by the rearwheels of the vehicle. Both planetary gearsets are thus in rotation iandthe speed of the planet gears and the sun gear of the front set arelower than they would be if the clutch 56 were not engaged and thefriction n the rear set should exceed that in the front set.

In the park position, as noted previously, the drum 3S is held by alatch 20|) (Fig. 6) engaging in one of a series of holes 198 in thedrum. At such time brake band 68 is also engaged, clutch 55 isdisengaged. The car then cannot move because the sun gear 45 of the rearplanet set is held by band 68 and the ring gear 42 of the rear planetset is held by the latch, so that the carrier 44 and driven shaft 30 areheld immovable. If the engine is operated under such conditions, clutch56 also engages. so that front sun gear 33 is also held, locking up thefront planet set as well, and requiring slip to take place in thehydraulic torque converter.

The following table shows the conditions obtaining in the principalclutching and braking devices in the several drives and settings of thecontrol components:

1 When engine is running.

Structural features of the hydraulic torque converter and l0ck-outclutch assembly The hydraulic torque converter may be fastened to thecrankshaft of an engine, in which event the driving shaft may be thecrankshaft of the engine. A flange portion 11 formed on the rear end ofthe driving shaft 10 is secured by bolts 75 to a relatively thin sheetmetal web 76 which is secured by screws 77 to the rotary casing portionof the hydraulic torque converter. Casing 15 is in turn secured at itsrear end to the pump member 12 of `the torque converter. The drivingcasing portion 15 is cast with integral cooling fins 82 to which a sheetmetal shroud ring 84 is secured. Shroud ring 84 carries the startingflywheel ring gear 85. Also secured to the front face of the member 15by the screws 77 beneath the web 76 is a somewhat heavier sheet metalweb 86 having a rearwardly offset annular portion 88 covering the innerends of the bolts 75. At its inner periphery, the offset web portion 88carries a forwardly extending cylindrical flange portion 89 which isfast with respect to a radial flange 90 formed upon a combined pilotbushing and uid conducting member, generally designated 92. Member 92has a piloted stem portion 94 extending into and rotatably supported inan axial pilot opening 95 in the end of the crankshaft 10, and isprovided also with a rearwardly extending concentric cylindrical wall 96defining a cylindrical central opening 98 which communicates with adrilled hole 99 extending axially rearwardly from the front end of thetransmission shaft 'a0 to a point near but spaced from the rear end ofsuch shaft.

The space between the cylindrical walls 89, 96 defines alconcentricannular chamber within which an annular p1ston 100 is slidable. Piston100 carries spline-like clutch teeth 102 formed upon the periphery of aflange 104 integral with the piston and extending outwardly directlybehind the rearwardly offset wall 88 of the web member 86. Splineportions 102 slidably interengage coacting spline portions 80 carried byan annular bracket 105 secured to the rear face of the offset portionS5. The piston 100 is movable rearwardly far enough so that theperipheral teeth 102 may also engage coacting clutch teeth 106 spacedand positioned correspondingly to the teeth 80 formed upon the innerperiphery of the ring 105, the teeth 106 being formed upon a hub 108fast upon the forward end of propeller shaft 20.

The turbine member 18 of the hydraulic torque converter is keyed to theperiphery of the huh 108. The toothed portion 102 of the piston 100 islong enough to bridge the spline portions 80-106, to clutch thecrankshaft to the turbine member 18, and thus eliminate the hydraulictorque converter from the line of drive.

An .annular chamber to the rear of the piston 100 is defined by therearwardly overhanging flange 104 of the piston 100 and the forwardlyoverhanging flange 110 of the hub 108. Within such chamber is a blockersynchronizer ring 112 having a `hub portion 114 slidable upon `acylindrical reduced rear extremity 115 of the wall 96 of member 92. Thelimit of rearward travel of the blocker synchronizer ring is defined bya snap ring abutment 116, while the rearward limit of travel of thepiston is defined by a snap ring abutment 118. The opposed faces of thepiston 100 and ring 112 are provided with a series of correspondinglyspaced sockets 120, 122 adapted to accommodate coil compression springs124. Alternated with the spring sockets 122 and projecting forwardlyfrom the ring 112 are a plurality of blocker pins 125 which extendforwardly far enough to engage, and always project into, coactingblocker pin sockets formed in the rearwardly directed face of the piston100. The sockets in the piston are of stepped configuration, each suchsocket having a cylindrical mouth portion 126 of substantially greaterdiameter than the pin 125. Enlarged portions 126 are deep enough so thatwhen the piston is fully drawn forwardly into the annular chamberbetween the walls 89, 96, the front ends of the pins 125 extend onlyinto the enlarged portions 126 of such sockets. Each such socket alsoincludes a deeper concentric portion 128 of a diameter to slidably fitover the end `of the corresponding pin when the piston is moved to therear. The clearance between the engaged socket portions 126 and the pins125 determines the amount of angular rotation or clocking permittedbetween the piston and the blocker ring. It will be noted that theblocker ring is also formed with a flat back face 130 which is yieldablyurged against a fiat front face 132 formed upon the hub 108. Due to thisfrictional engagement, which is imposed `by the springs 124, the blockerring tends to rotate with the hub 108 and turbine 18, and whenever thepump and turbine are `rotating at different speeds, the drag between thesurfaces 130, 132 holds the blo-cker ring turned with relation to thepiston 100, so that the pins 125 partially overlap the shoulder 133which joins the reduced socket portion 128 to the enlarged mouth portion126 of each socket. Each shoulder 133 is thus blocked by the pin 125,and the piston is thereby held against moving to the rear, so that itstoothed clutch portion 102 cannot bridge the toothed portions 80, 106.lt will be apparent that upon synchronizing of the parts 12, 18,however, or a torque reversal, if pressure is present in the chamberspace 91 at the head of the piston, the piston can move rearwardly tolock the torque converter by bridging the clutch portions 80, 106.

lt will be observed that the right side of piston 100 is exposed to thepressure in the hydraulic torque converter assembly, but such pressureis lower than the fluid pressure delivered to the cylinder 91 from thesupply and control system (to be described) when the lockout clutch isto be engaged. When the pressure in cylinder 91 is relieved, theconverter ypressure acts on the right side of' piston 1001.0 discugagethe clutch.

The hub 108 is splined to the turbine 18 at 134 and is splined at 135 tothe forward end of the transmission shaftZi).

Surrounding the transmission shaft 20 `and extending rearwardly from aposition approximately beneath the conter plane of the hydraulic torqueconverter is a fixed sfceve 138, which at its rear end terminatesadjacent the harige which connects the internal gear 24 to the shaft 20.Sleeve 138 is secured in a fixed bearing supporting flange 142 carriedby a partitioning `web 144 forming a part of the casing structure. Theforward cud of the sleeve 138 is splined as indicated at 145, andsecured thereto is the inner race or hub portion 146 of the ovcrrunniugbrake assembly 21 for the stator 16 of the hydraulic torque converter.Other elements of the ovcrrunning brake, which may be of conventionalspragtype, include sprags 148 and a ring 150 which is splined at 152 tothe inner periphery of the stator. The stator and overrunning brake arealso located by side thrust plates 154, 155 which also position thesprags 148.

The impeller or pump member 12 of the torque converter is secured at itsinner periphery to a flange 156 formed upon the front end of a hollowshaft 158, journaled in a bearing 179 in the front casing section 164 ofa hydraulic pump shown as of the gear-type and generally designated 165.Pump casing section 164 is rigidly secured to and forms in effect a partof the partition 144,

as indicated at 230. The rear web 183 of the carrier is secured to thefront web by integral bosses 232 and headed pins 233 and also by theplanet shafts 234 upon which the planet gears 48 are mounted. The sungear 45 of the rear set is shown as formed integrally upon a sleeveportion 235 which also serves as a part of a manifolding structure fordistribution of hydraulic actuating duid, as will presently bedescribed. Sleeve portion 235 is journaled in a bearing collar 236formed integrally with a partition 238 which constitutes a part of ahousing for a rear pump assembly generally designate:1 2.40, drivable bythe shaft 30 through the agency of a driving sleeve 242 rotatablysecured to the shaft. Pump gear 243 is splined to sleeve 242. Theinternal diameter of the sleeve 235 is substantially greater than theexternal diameter of the shaft 30, and another sleeve 244 is tightlyfitted into the interior of the sleeve 235 and coacts therewith inconducting the uid to the clutching means in the drum 50, the sleeve 244also being of larger internal diameter than the shaft 30, so that n cle....icc exists between these parts. There is also clearance between theshaft 30 and the gear portion 45 at the forward end of the sleeve 235,so that o certain amount of lloating movement is afforded all of theparts mounted upon the sleeve 235.

Also xedly attached to the flange 252 is an angular web portion 258which is substantially of truncated conic form and extends angularlyrearwardly to support the brake drum portion 66, which is integraltherewith, in a position in transverse alignment with the bearingsupporting hub portion 236. Although the load resulting from theapplication of the brake band 68 is tranunittcd through the bearingmeans 423, serving to journal the rear sun gear 45 and the manifoldstructure 2315. 244 in the rear fixed hub 236, such sun gear andmanifold portions are not rotating when the brake is applied, and noload is applied to thc gear train at such time, the brake drum 66 beingoffset rearwardly to lie directly over the bearing and hub portions 423,236.

The casing structure which surrounds the gearing and clutch and brakeportions last described may be of gen erally conventional construction,and is shown as a cast housing 260 having a removable bottom oil pan262. To the rear of the pump 240, which may also be of the gear-type,the housing is reduced to define a locating shoulder portion 264 whichpositions the rear half 265 of the rear pump casing, and also positionsthe portion 238 previously described. An antifriction bearing for therear end of the shaft 30 is located in a bearing flange 266 formedintegrally with the pump casing portion 265. The bearing assembly isgenerally designated 268.

Rearwardly of the pump, the housing is provided with a reduced portion270 which houses driving gears 272, 274 for the governor means, and alsohouses the governor structure. A speedometer driving gear 275 may alsomesh with the gear 272 within the rear casing portion 270.

Referring to Fig. 3, it will be seen that the governor incorporates apair of tlyweights 276 pivoted upon horizontal pins as 277 carried by ahollow governor shaft 278. The gear 274 is formed upon the upper end ofthe governor shaft. Each lyweight has an integral finger portion 280projecting through a slot 282 in the wall of the hollow shaft 278 andinto over-engaging relation with a plunger 284 extending into the hollowshaft. Plunger 284 bears downwardly against the top of a valve member285 which is slidable in a sleeve or governor valve housing 279, pressedinto a hole 287 in the housing 270, and which is urged upwardly againstthe finger portions 283 by a compression spring 286. There is norelative rotation between the plunger and the linger portions due to apin 281, the ends of which project into slots 282 through which thelinger portions project and therefore the finger portions and theplunger rotate together with the gear 274. The plunger is slidable androtatable in the upper portion of sleeve 279. At its lower end, thespring bears downwardly against another valve element 288 slidable inthe sleeve 279. The sleeve has suitable ports and passages and serves asa valve body for the valves 285, 288. The action of such valvecomponents will be considered hereinafter.

Brake bands and brake details The applying means for the forward speedsbrake band 68, as best shown in Fig. 5, is arranged to apply the brakeband at all times except when fluid is delivered to the actuatingservo-motor cylinder 450. The brake band 68 may be formed from anintegral length of sheet metal having formed hooked end portions orpockets 452, 454 at the applying end and the anchored end thereof,respectively. At a plurality of spaced points, as indicated at 455, 456,the band is provided with localized areas of reduced thickness extendingthe full Width thereof, and which in eEect constitute hinges, the areasbetween and on either side of which act as relatively rigid brake shoesections. This band may be made of a one-piece stamping of heavy enoughmaterial to maintain its shape in processing and in applying the lining458, which may be bonded thereto. With this arrangement, the band can bemade perfectly round. The sections at the ends remain heavy where theloads are applied, and all three of the shoe sections being heavy. Thesesections are lowly stressed. The reduced sections 455, 456 are highlystressed, so that all of the bending when engaging or disengaging theband will occur at the reduced sections. The band is thus very flexiblein its over-all nature, and yet even with hard usage maintains its shapeand has perfect Contact with the drum, and therefore excellent wrappingqualities. The anchored end hooked portion 454 ot' the band receives astrut 460, the other end of which is received in a thrust cap 467. Thescrew 462 is provided at its inner end with a reduced axial pilotportion 471 and the cap 467 is provided with an axial recess into whichthe pilot rotatably tits, so that the cap is retained upon the end ofthe screw, but the screw can be turned without rotating the cap. Theadjusting screw permits the anchored end portion 454 of the brake band68 to be fixed in any desired position. The strut is made in the form ofa plate the ends of which are rounded to fit into the two pockets, oneof which is formed by the hooked end 454 carried by the end of the band,and the other of which is in the form of a transverse slot in the end ofcap 467. Thrust cap 467 is adjustably supported and backed up by theadjusting screw 462, which is mounted in a side of the transmission case260 in a thickened portion 264, the screw being rotatable independentlyof the cap. A lock nut 465 is provided for the adjusting screw. Theother end of the band is likewise pivotally connected to a strut 466,similar in construction to the strut 460, which is actuatable by an arm468 pivoted upon a pin 470 lixedly supported in the transmission case. Alonger and substantially horizontal lever arm 472 integral with the arm468 is normally urged in a direction to cause the brake band to contractand engage the drum by means of a compression spring 474. The springreacts at its upper end against a portion 475 of the transmission case,and at its lower end is seated in a retainer cup 476, which in turnholds a ball portion 477 which bears against a socketed portion 47Sformed in the end of the arm 472. The cylinder 450 contains a piston 480to which a stem 482 is attached, bearing upwardly against a socketedportion 484 formed in the bottom of the arrn 472. As shown in Fig. 5,the cylinder 450 is secured to a bottom plate portion 485 which ismounted on the portion of the transmission casing below the actuatingmechanism for the brake band, the stem 482 extending upwardly through ahole 486 in the plate 485. A relatively light spring 488 holds thepiston and stem 482 up against the socketed bottom of the arm 472, butthe spring 488 is weaker than the spring 474 and therefore cannotrelease the brake, which is held applied by spring 474 except when uidunder suicient pressure is delivered to cylinder 450. The fluid passageleading to thc cylinder 450 is designated 490.

The details of the breite band 36 for actuating the reverse brake, andits mounting and actuating means, shown in Fig. 4, are similar -to thoseofthe brake band 68, shown in Fig. 5, however the lever is arranged toengage the band by the force exerted by the piston contained in acylinder 700. The fluid passage Jleading -to the cylinder 700 isdesignated 704. Therefore, when fluid is delivered to the servomotorcylinder 700fthe brake is applied and when the fluid is released from`the cylinder the brake is released.

Hydraulic control' system: Fluid Supply and pressure regulation Thecomponents of the liuid supply and control system are indicated in Fig.6, principally in diagrammatic form, although some structural featuresare shown. Whenever the shape of a structural part in Fig. diiers fromthe shape indicated in the other figures, however, the other figuresdepict the actual construction and the change thereof in Fig. 6 ismerely for simplification and added clarity of diagramming, as will beapparent. In Fig. 6, the intake to the front pump is indicated at 300.As indicated in Figs. lA and 1B, such intake is actually formed bycoacting passage defining portions `in the partition 144, transmissioncase 260 and the pump housing. The lower terminus of such inlet passageis delined by an aperture 301 in the wall of a lower forward portion ofthe transmission case which is overlapped by the partition 144, theaperture 301 opening into the transmission case below the oil leveltherein. At its upper end, the inlet passage system to which the generaldesignation 300 is applied terminates in an aperture 303 extendingthrough the rear cover plate 167 of the front pump housing, the aperture303 constituting the inlet of the front pump. The front pump outletpassage is generally designated 305 in Fig. 6 and leads to an assemblyconsisting of pressure regulating valves 306, 308, and a check valve 310arranged to prevent backow to the pump. The rear pump 240 has an inlet312 which also communicates with the sump and an outlet passage 314which communicates through a branch passage 315 with a check valve 316.

The valve 306 includes a bottom spool 318, a middle spool 320, and a toppiston portion 322. A spring 324 urges the valve upwardly. When thevalve is in its raised position in which `it stands when neither pump isdelivering pressure, a vent port 325 formed in the side of the body ofthis valve is sealed off by the spool portions 318, 320. At such timealso, the bottom spool 318 seals off a-brapch conduit 326 communicatingwith the front pump outlet passage 305, and the spool and pistonportions 320, 322 coact to seal off a second branch passage 328 whichalso communicates with the passage 305. When the front pump deliverspressure, which it does whenever the engine is in operation, thepressure bears downwardly upon the top of spool 320 tending to move thevalve 306 downwardly. The valve then acts as a pressure regulatingvalve, since when the pressure rises above the desired maximum, it movesdownwardly until the top edge of the spool 318 moves into the branchpassage 326, and the neck portion 330 of the valve which is longer thanthe space between passage 326 and port 325 then connects thelast-mentioned passage and port, and the valve allows a throttled escapeof excess fluid and maintains a desired maximum pressure.

The valve 308 is urged upwardly by a spring 332 which is calibrated tomaintain the rear pump outputpressure slightly higher than the frontpump output pressure. The valve 308 includes a bottom spool portion 336,a middle spool 338 and a top piston portion 340. A neck portion 342joining the spool portions 336, 338 conforms `to `the width of a chamber344 which communicates with a dump port 345, and the neck portion 342 islonger than the space between chamber 344 and a branch passage 346 whichcommunicates with the front pump outlet 305. T he upper face of spoolportion 338 is exposed to the rear pump pressure obtaining in branchpassage 315. When the valve 308 is moved downwardly by rear pumppressure, it dumps the front pump 165. This is accomplished by the spool336 which moves downwardly into the port 347 under the influence of therear pump pressure exerted on top of spool 338. Spool 338 issubstantially shorter axially (in a vertical direction) than the chamber344 to which the Vent port 345 is connected, so that the spool 338 canmove downwardly into the charnber 344, and can then coact with a throatportion 339 of the valve body between chamber 344 and passage 315, tothrottle the rear pump output, to maintain it at a desired maximumpressure, without blocking the connection between the ports 347, 345,which remains effective to dump the front pump so long as the rear pumpis delivering suicient pressure.

Rear pump pressure also communicates through a reduced orilice 348 and abranch passage 350 with the spring chamber 352 at the lower end of valve308. Chamber 352 communicates with the sump through a port 354. Thisconstitutes a bleed which is always open until the front pump is dumped,but which is closed when, and just as, the spool 336 moves downwardlyfar enough to dump the front pump. By virtue of this arrangement, apredetermined minimum rear pump volumetric output is required to dumpthe front pump, and the valve 308 is not forced down by the rear pump,to dump the front pump, until both the pressure and the volumetricoutput of the rear pump are suliicient so that dumping of the front pumpcannot cause an undue drop in pressure in the system. Without theprovision of the orifice 348 and the vent 354, there is a tendency forthe valve 308 to hunt and buzz, and the pressure in the system tends touctuate accordingly. It will be appreciated that without this bleedarrangement, even with the car rolling very slowly, the pressure mightbuild up in the rear pump output sufficiently to move the dump valve 308down before the volumetric output of the rear pump was sufficient toproperly supply the system and take care of leakage.

The rear pump also communicates through an orifice 333 and Va passage334 with a chamber 335 at the head of the piston portion 322 at theupper end of valve 306, and also with a chamber 337 at the head of thepiston portion 340 at the end of valve 308. The effective pressuredelivered to chambers 335, 337 is regulated by a variable orifice S24controlled by the position of the throttle. The downward pressure uponthe valves 306, 308 exerted by the uid in the chambers 335, 337constitutes a counterbias partially offsetting the effect of the valvesprings 324 and 352, and the arrangement is such that when the car isstanding still, there is no counterbiasing pressure in the chamber 335,because the rear pump is not operating, and the front pump outputpressure is accordingly capable of rising to its maximum value. This isdesirable for the reason that with the car standing still the torquemultiplication of the torque converter may be `at its maximum, whichrequires the highest pressures in the servomotors in order to hold theclutching and braking means properly despite such high torqueconditions. When the throttle is open with the vehicle in motion, thepressure in chambers 335, 337 bears an inverse ratio to the extent ofthrottle opening. Due to the decrease in such counterbias as thethrottle is opened wider, the output pressure rises to supply higherfluid pressures for operating the clutches and brake bands, which isdesirable when higher torque demands are being made upon thesecomponents. This aspect `of the control will be considered furtherhereinafter.

Hydraulic control system: Valvular control components The output sidesof the check valves 310, 316 communicate with a conduit 362 whichcontains a reduced orice 364 and which leads to a side port 365 of aselector valve 366 which may be manually operable, as by a control levermounted on the steering column of the vehicle. Beyond the orifice 364,passage 362 also communicates through a branch passage 368 with acushioning chamber or pressure dome 370 and an inwardly opening checkvalve 372, the outlet 374 of which is above the oil level in thetransmission casing.

A branch passage 375 connected to the main lluid supply passage 362between the orifice 364 and the check valves 310, 316 leads to a sideport 376 of a converter valve 378. The valve 378 is actuatable by apiston portion 380 which bears against its upper end. The valveincorporates a cylindrical valving spool portion 382 located below andsomewhat smaller than the piston portion 380, and another piston portion384 at the lower end of the valve spaced from and connected to the spoolportion 382 by a reduced neck 385. The valve is urged downwardly by aspring 386 bearing downwardly upon the piston 38u and reacting upwardlyagainst a perforated cover plate 338, the apertures 390 in which connectthe spring chamber 392 at the upper end of the piston 380 with a chamber394. Spacedly below the inlet port 376 is an outlet port 396 whichcommunicates with a passage system generally designated 398, whichcommunicates with the interior of the hydraulic torque converter. Thepassage 375 is also connected by a branch passage 402 to a chamber 400below the piston portion 384. It will be noted that the supply to thepassage 375 which is delivered to the converter valve 378 is derivedfrom the main supply passage 362 after the uid has passed through thecontrol valve system formed by the valves 306, 308 previously described.Valve 378 controls the pressure in the interior of the hydraulic torqueconverter in relation to main pump output pressure in a manner whichwill presently be described.

In the actual transmission construction, some of the oil passages arenot illustrated, being out of the plane of the paper, but the provisionof the requisite oil passages is well within the capability of personsskilled in the art. The passage system 398 communicates with alongitudinal passage 399 (Fig. 1A) which extends through the spacebetween the outside of the sleeve 138 and the inside of the sleeve 138and which delivers oil to the interior of the ovcrrunning brake 21within the stator 16 of the hydraulic torque converter. The oil thenmoves radially outwardly through passages extending through theoverrunning brake, and which are not specifically designated byreference numerals, and into the interior of the torque converter. Thereturning oil from the torque converter moves rearwardly through apassage 401 between the shaft and the sleeve 138 to a radial hole 410formed in the sleeve 138 just to the rear of the plate 167 which formsthe rear section of the casing for the front pump 165. The hole 410communicates with a cushioning chamber 412 which is formed by arearwardly offset portion of the partition 414 which closes the forwardend of the gearing compartment defined by the casing portion 260. l'hcupper portion of the chamber 412 contains trapped air forming aresilient cushion. An outwardly open check valve 406 also communicateswith the chamber 4t2, and the returning oil from the torque convertercan pass outwardly through an opening 408 and through 'the check valve406 and passages 415, 416 and 419 to lubricate the rotating parts whichare supported in the fixed hub 142 of the partition 414, as will be seenupon examination of Fig. 1B. When the piston 100 moves rearwardly toengage lock-out clutch 22, it must dsplrce oil from the torqueconverter. It will be sec-n that the provision of the cushiong chamber412 and chuck valve m6 permits the piston 100 to move more 14 rapidly inboth directions. The cushioning chamber 412 is also diagrammaticallyillustrated in Fig. 6 located in the line leading to the torqueconverter although in the structural embodiment shown in Fig. 1A it isactually located in thc outlet from the torque converter'. The action is`ub-stantially the same in either case.

.as also shown in Fig. 6, the passage system 398 leading to thehydraulic torque converter is connected to the rear pump output throughan orifice 908 and check valve 906 and passages 404, 405. The checkvalve 906 opens toward the passage 398, so that fluid can be supplied tothe torque converter from the rear pump when the vehicle is moving, evenbefore the front pump is dumped, so that when the front pump is dumpedthere is no sudden undue drop in pressure in the system supplied by therear pump. Experience has shown that the presence of the orifice 908 andcheck valve 906 provides a damping action which prevents buzzing of theconverter valve.

A piston-type relief valve 425 is arranged in axial alignment with theconverter valve 378, the chamber 394 being arranged between valves 425,378, and the heed of valve 425 being exposed to the pressure within suchchamber. Valve 425 is urged inwardly of chamber 394 by a spring 426 andthe pressure in the chamber which communicates with the passage 398leading to the converter tends to move the valve 425 outwardly toestablish communication between chamber 394 and a vent port 428. Thevalve 425 can open to allow escape of uid when thc piston v|00 moves ina direction to engage clutch 22.

The illustrated control arrangement is so designed that the vehiclenormally starts in the second speed or intermediate gear, the lowforward gear being employed only as an emergency low. With the selectorvalve in the drive position in which it is shown in Pig. 6, which is theposition in which it is normally kept during all forward driving, exceptduring emergency conditions, the fluid from the main line 362 enters thevalve at port 365 and leaves the valve at port 433, these ports beingconnected by a reduced portion 434 of the valve and being isolated fromother parts of the valve chamber by valve spools 435 and 436. From port433, the fluid passes through a passage 438 and connecting passagewaysleading to the actuating cylinder 67 for the clutch assembly 55, whereit may act upon the piston 62 to engage such clutch. A portion of suchpassageway system shown in Fig. 1C cornprises a manifold inlet port 440formed in the sleeve 235, a radially drilled hole 442 in such sleeve, alongitudinal channel 440 formed in the manifold sleeve 244, acommunicating manifold port 445 (Fig. 1B), a groove 446 in the outerwall of sleeve 235 and a passage 447 extending through the surroundingwall of hub 225. The uid thus enters the space 67 behind piston 62 toapply clutch 55.

The passage system leading to the actuating cylinder 67 for the clutch55 is designated in Fig. 6 by the general reference number 439. A branchpassage connected to the passage 439 is designated 494 and leads to aport 49S formed in the side of the governor valve housing portion 279and opening thereinto in a position such that it is normally open to adrain port 502 by the neck portion 503 of the governor actuated valve285. A branch passage 496 connected to the passages 494, 495 opensthrough a lower portion of the governor valve housing 279 in a positionsuch that it is normally covered by the lower governor valve 288. Theport which forms the terminus of the passage 496 is denoted 498. Whenthe valve 285 is moved downwardly a predetermined distance, it connectsthe port 495 to a port S00. It will be noted that when the valve 285 israised, the port 500 is connected to the vent port 502, but that thevent port 502 is closed, and the ports 495--500 are connected, when thevalve moves downwardly. Connection of the ports 495, 500 supplies fluidto a passage 504 leading to a chamber 505 at the lower end of a shiftcontrol valve, generally designated 506. The fluid in the chamber 505acts upwardly upon a piston portion 508 formed at the lower end of thevalve and also upon a shoulder 510 which joins the piston portion 508 toa larger spool portion 512. The lower part of the spool 512 issurrounded by another valve chamber 514, and it will be noted that thereduced portion 515 of the valve casing structure through which thepiston portion 508 extends is somewhat larger than the piston portion508, so that communication is established between the chambers 505, 514(except when the shift control valve is raised, at which time suchcommunication is closed by an enlarged head portion 509 on piston 508).

Fluid from the rear pump is also supplied to the chambers 505, 514 byway of passages 314, 405 and through an orifice 516 and a passage 518leading into the side of chamber 514, so that rear pump pressure alsotends to lift the valve 506. A branch passage 520 connected to thepassage 518 leads to a port 522 formed in the side of the governor valvehousing 279 nearer the hottom thereof, but above the restricted variableorifice 524 which opens through the side of such housing, near thebottom of the path of movement of the valve 288. Oritice 524 isconnected to a passage 525 which also conimunicates with passage 334leading to the counterbiasing chambers 33S, 337 of the pressureregulating valves 306, 308. and is also connected to the rear pumpoutput passage 314 through orice 333, as previously explained.

The oritice 524 may consist of a plurality of small holes arranged invertical relation, or of a narrow vertical slot. the totalcross-sectional area of all such holes, or of the full slot, being of adesired relation to the cross section of the orice 333, through whichthe orice 524 is connected to the rear pump output line 314. Accordinglywhen the throttle is open relatively wide, the pressure from the rearpump is substantially relieved in the counterbiasing chambers 335, 337of the pressure regulating valves 306, 308, and the output pressure inthe main line is relatively high, whereas when the throttle is closedthe chambers 335, 337 receive the full pressure from the rear pump andthe output pressure in the main line is relatively low. With no rearpump pressure, for instance when the car is standing, there will be nopressure in the chambers 335, 337 and the output pressure in the mainline is at its maximum.

The valve 288 is moved upwardly whenever the accelerator pedal isdepressed, and such upward movement stresses the spring 286 to increasethe upward bias upon the valve 285. The actuating means for the valve288 is shown as comprising a rod 52.6 pivotally connected to an arm 528which is actuatable by the accelerator pedal or throttle control shaft531. A spring-pressed detent 532 is positioned in the path of an angularportion 534 of an arm 530 that is connected to the throttle controlshaft. so that the operator, in depressing the accelerator pedal beyondthis point, will be able to feel the increased resistance and know thatsuch predetermined detent position has been reached. The limit ofaccelerator depression is indicated as fixed by a stop wall 535 whichengages the side of the detentwhen the accelerator is fully depressed.

A reduced stem portion 536 of the valve 288 normally provides connectionbetween a port 538 and a port 540 formed in the side of the governorvalve housing 279. Port 538 is connected by a branch passage 542 toithepassage 504` while port 540 is connected by means of a passage 544 to achamber 545 at the lower end of a lock-ont clutch valve generallydesignated 546.

A branch passage 550 is connected to the outlet from the check valves310, 316 via passages 368, 362, and serves to conduct uid from the mainfluid supply line 362 around the selector valve. Such fluid is adaptedto be delivered by way of the anticreep `valve 360 to a passage Vsystemgenerally designated 552 leading to the actuating means for the clutch56.

Passage system 552 is also conducted through the manifold means shown inFigs. 1B and 1C and formed in the portions 235, 244 and 225, the uidbeing delivered to the space 69 between partition 54 and the piston 65.

Conduit 552 through which iluid is supplied for the operation of theclutch 56 is connected through the bearing support 236 (Fig. 1C) to aperipheral groove 564 in the outer manifold sleeve 235. Groove 564 is inturn connected through a radial hole 565 to a longitudinal groove 566 inthe inner manifold sleeve 244. Groove 566 leads forwardly through theassembly of manifold sleeves to a port 568 (Fig. 1B) extending throughthe outer manifold sleeve and communicating with a radial hole 570 inthe hub 225, fluid being fed through the hole 570 into the cylinder 69.

It will be noted that the lluid supply passage 550 is also connected toa side port 572 of a release or timing valve 574 for the clutch 56.Valve 574 has spaced upper and lower spools 575, 576 joined by a reducedneck 578. The neck is long enough and the parts are so proportioned thatwhen the valve 574 is in the down position shown in Fig. 6,communication is established through the valve chamber between the port572 and an outlet port 580. Outlet port 580 communicates throughbranching passages 582, 584, with a port 585 formed in the side of thechamber of valve 360 and with a chamber space 586 at the lower end ofthe valve 360. It will be noted that the valve 360 also includes upperand lower spool portions 588, 590 spacedly connected by the neck portion556, but that the lower spool 59.0 Vis substantially smaller than theupper spool S88. A separate but coaxially slidable piston 592 isarranged to bias `the valve 360 in the opposite direction from thedirection in which it is urged by the spring 555 whenever duid isdelivered to a chamber 594 from the realt pump, chamber 594 beingconnected to the rear pump output passage 314 by passages 595, 405. Theproportioning of these parts is such that the rear pump pressure issucient to move the valve 360 all the way up against the resistance ofspring 555, whenever the rear pump is turning faster than a rate whichwould correspond to a very low vehicle speed.

Since the disclosed system is intended to start the vehicle in thesecond gear ordinarily, and the clutch 56 is not employed in the secondgear drive, the uid supply to the passage 552 is interrupted wheneverthe vehicle is moving in second speed (or normal starting gear settingof the selector valve 366). This interruption is accomplished throughthe valve 574. Fluid is delivered through a branch passage 598 whichcommunicates with the outlet passage 438 from the selector valve 366 toa chamber 600 formed at one end of the chamber of valve 574. Wheneverthe selector valve is in the drive position as shown, with the enginerunning and the car standing still, the valve 5744 held up by thepressure in the chamber 600 and the valve v3R60 Vstays down far enoughto cut olf the port v5.35,. No Huid then reaches line 552 except thethrottled, reduced pressure duid which passes through the partiallyclosed port 602 and out via port 560, and which holds the valve 360 in apartially raised throttling position by reason of the `fact that thespool 588 is bigger than the spool 4591i). This reduced pressure fluidmaintains the clutch 56 engaged at light pressure (as a part of theanticreep means). As soon as the vehicle begins to move, rear pumppressure raises the valve 360 so that the spool 590 blocks the port,602. The valve 574 being also raised, all supply to the actuating meansfor clutch 56 is cut on, and huid is supplied only to the actuatingmeans for clutch 55 through passage 439, as previously described. Thebrake hand 68 is also engaged, since no uid is being supplied to thepassage 490`leading to its releasing cylinder 450.

lt will also be noted that the valve 574 is biased downwardly bypressure delivered to a chamber 605 formed at the upper end thereofthrough a conduit 606 connected to the conduit 398 through which uid issupplied to the hydraulic torque converter. The converter relief valve378 is set for a pressure lower than the front pump pressure determinedby the regulating valve 306. Referring to the converter valve 378, itwill be seen that the lowermost piston portion 384 is smaller than thepiston 380 at the upper end of the valve, and that the valve 378 isbiased downwardly partially by a spring 386, but principally byconverter pressure acting downwardly upon the top of piston 380. Fluidpressure in the main line 362 tends to move the valve 378 upwardly untilspool 382 partially uncovers port 376, to establish communicationbetween the ports 376, 396. The valve 378 thus acts as a pressureregulating valve in supplying Huid to the hydraulic torque converter,maintaining the pressure in the hydraulic torque converter at a lesservalue than that in the main line. Whenever the pressure in the converterand passage system 398 is such that the elect of such pressure, plus theforce of spring 386, in chamber 392, cannot hold valve 378 down againstthe main line pressure in chamber 400, the pressure in the chamber 400raises the converter valve 378 to allow enough tluid from the passage375 and main line 362 to enter the passage 398 to raise the pressure inthe torque converter system to the desired value. If the rear pump isnot operating, the pressure is held in the converter system by the checkvalve 906, and it will be noted that as soon as the engine is started,front pump pressure in the main line is effective to bring the converterpressure up to the desired value. The converter pressure is also limitedto a value less than `the front pump output pressure, as stated, andthus even when only the front pump is operating, the pressure in thechamber 600 at the lower end of release valve 574 is greater than theconverter pressure in chamber 605 at the upper end of the valve 574, sothat such valve is biased upwardly so long as Huid from either pump isbeing supplied through the selector valve to the passages 438, 598. Whenthe engine is stopped, however, the pressure trapped in the convertersystem acts upon the upper end of the valve 574 to positively return itto the position shown.

Hydraulic control system: Anticreep The operation of the anticreep valvecorresponds generally to the operation of the anticreep valve shown inthe embodiment of Fig. 3 of my copending application Serial No. 171,042,filed June 29, 1950. When neither pump is operating, this valve standsin a position corresponding to the lowermost position of its movement,as illustrated in Fig. 6, toward which position it is urged by thecompression spring 555. At such time, a reduced mid section 556 of thevalve provides communication between an inlet port 558 which isconnected to the passage 550 and an outlet port 560 to which the passage552 leading to the actuating means for clutch 56 is connected.

lf the vehicle is moving in the starting gear, and is slowed downsuiliciently with the selector valve still in the drive position andbefore an upshift to direct drive has occurred, the valve 360 moves downas soon as the drop of rear pump pressure permits (rear pump pressurebleeds through the orifice 348 and vent 354 as previously described).The valve 574 stays up, however, since the engine is running andsupplying pressure to thechamber 600. The front pump is also supplyingpressure to the inlet port 602 of the valve 360. Since the upper spool588 of the latter valve is larger than the lower spoolA 590, aspreviously noted, valve 360 now acts as a sellthrottling valve, beingurged upwardly so that the spoolE 590 tends to close cti communicationbetween the ports 558, 560 to the extent required to reduce the pressurein the passage 552 to a relatively low value, which holds the clutch 56engaged at light pressure.

It will be observed that if the anti-creep valve 360 moves up farenough, the top spool 588d opens the port 585, and that thisopeningcommences at approximately the same time as the spool 5,90-`completes the closing of port 602, during such 'upward movement of thevalve.

The release valve574 is raised at this time, and the open ing of theport 585by theanti-creep valve 36th thus permits a venting of theservomctor for the clutch 56. This venting occurs at the side vent port608 of the shift control valve 506. The shift control valve is down atsuch time, since the vehicle is in the starting gear, and the ventconnection is by way of port 560, past the neck 556 of the anti-creepvalve and via port `58S, passage 626, port 580. past the vneck 578 ofthe release valve S74 and by way of port 620, passage 618 and pcrt 612to the shift control valve, and past the neck 614 of the shift controlvalve to the vent port 668. During the throttling action of theanti-creep valve 360, which maintains Vthe light holding pressure in theservomotor for clutch 56, to hold the car against creeping, therefore,the vent opening just described fixes a limit upon the pressure whichcan be developed in the servomotor, since if such pressure rises toohigh. the vent just described can open sutliciently to allow thepressure in the servomotor, and thereby the holding etllort exerted byclutch 56, to fall to the desired value. Ahe clutch S5 is also engaged,since front pump pressure is being supplied to the passage 439 and theband 68 is of course also engaged. Both planetary gearsets are thuslocked up and both gearsets are also held stationary by the band 68, sothat the propeller shaft is held against rotation and slip takes placein the hydraulic torque converter'. Since the clutch 56 is held engagedwith relatively light pressure under such conditions, this anti-creepholding means is not unduly severe. In event the car should be pushed,or other substantial force applied to it. the clutch 56 can slip.

Hydraulic control system: Ratio changes When with the vehicle travelingin the starting gear range, the speed of the vehicle becomes greatenough, the upper governor valve 285 is moved downwardly to connect theports 49S, 500. Fluid from the selector valve outlet 438 is thendelivered through the passages 494. 504 to the lower end of the shiftcontrol valve 506, and such valve is moved upwardly to cause the spool512 thereof to close on vent port 608 and to connect together two ports610,612 of the valve 506. Such ports are then connected by a reducedneck portion 614 which unites the lower spool 512 with the upper spool615 of the valve. Communication is thereby established between u passage616 which is connected to the passage 439 which supplies actuating Huidfor clutch 55, and a passage 618 which is connected to a port 620 formedin the side of the casing of the release valve 574 for clutch S6. Port620 is located in a position to be blocked by the upper spool 575 of.valve 574 when such valve is down. The passage 618 is also connectedlt'o a port 622 formed in the side of the chamA ber of a releasing valve625 for the forward drive brake band actuating means, comprising thecylinder 450 previously described.

It will be remembered that both of the clutches 55, 56 must be engagedfor the high speed drive. Both of thc valves 574 and 366 being raised,the fluid is delivered from the port 620 past the reduced neck portion578 oi the valve 574 and through port 580, passage 626, port 585, pastthe reduced neck portion 556 of valve 360 and through port 560 andpassage 552 to the actuating cylinder 69 for the clutch 56.

When fluid is supplied for actuation of the clutch S6 through thepassage 618`in the manner described, it is also delivered through abranch passage 628 to a chamber 630 at the lower end of the valve 625.Although converter pressure is delivered from the passage 606 to achamber 632, at the upper end' of the valve 625, the pressure in line618 and chamber 630 is higher than the converter pressure, so thatthevaive 625 is then raised to establish communication between the port622 and the passage 490 leading to the releasing mechanism for theforward speeds brake band 68. When valve 62S is thus raised, a lowerspool portion 634 thereof blocks a lower port 642 thereof,

I9 and the reduced neck 638 connects the port 622 to a port 640 to whichthe passage 490 is connected. Brake band 68 is thereby released for thedirect drive.

A passage 635 is connected to the port 642, which is spaced slightlybelow the port 640 of forward release valve 625, so that when the valve625 is lowered, the lluid supply passage is cut off at the port 622, andcommunication is established between the two passages 490 and 635. Undersuch conditions, the selector valve 366 being in the D position, thereleasing cylinder 450 for the brake band 68 is connected to atmosphereor vented, since the passage 635 terminates at a port 644 in the side ofthe selector valve 366, port 644 then being in communication with areduced portion of the selector valve defined by a neck 645 between thespool 436 and a spool 646 spacedly to the left thereof. An angularpassage 648 in the spool 646 connects the chamber space defined by thereduced neck portion 645 with the side of the enlarged spool portion646, and with the selector valve in the forward drive1 position shown,the angular passage 648 registers with a vent port 650. The valve 625will thus be seen to constitute means for closing the vent for theforward speeds brake release cylinder 450, and for connecting the supplyof actuating fluid thereto to release this brake in the high speed ordirect drive.

When with the car traveling in the high gear ratio, the acceleratorpedal is manipulated throughout its normal range only, there is aconstant connection between the outlet passage 504 of the upper governorvalve 285 and the passage 544 leading to the chamber 545 at the lowerend of the lock-out clutch valve 546. Fluid from the selector valveoutlet 438 is resultantly delivered to the actuating means for thelock-out clutch 22 previously described for the hydraulic torqueconverter. Such uid moves through the passages 438, 439, a branchpassage Y 660 to a port 662 in the side of the chamber of the valve 546.Valve 546 being in its raised position, the port 662 communicates withan outlet port 664 past the reduced portion of the valve dened by theneck 665 which joins the upper and lower spool portions 666, 668. Atsuch time, the vent passage 670 is closed by the lower spool 668. Thechamber 672 above the upper spool 666 is connected to the converter line398 by the passage 606, so that the valve is returned to the loweredposition by converter pressure, when the pressures fall away in theother parts of the control system. The outlet port 664 is connected to apassage 674 which communicates with the annular piston space 91 betweenthe flange 90 of the pilot member 92, and the piston 100, shown in Fig.1A. The passage 674 is connected through a passage 675 (Fig. 1A) to aperipheral groove 676 formed in the shaft 20 within the area surroundedby the bearing supporting portion 142. Groove 676 communicates throughradial passages 678 with the axial hole 99 in the shaft 20, which inturn cornmunicates with the pilot bearing socket 98 (Fig. 1A) from whichradial passages 680 extend outwardly into the piston chamber 91.

Whenever, with the car moving in high gear, the accelerator pedal ismomentarily released to relieve the torque upon the blocker ring 112,the lock-out clutch will engage, since fluid pressure is present in thepiston chamber 91, and the piston 100 will move rearwardly to engage thelock-up clutch as soon as it is unblocked in thc manner previouslydescribed. The drive will then continue with the torque converterlocked-out until the car slows down to a predetermined speed.

If the car slows down to a predetermined speed without full depressionof the accelerator, the upper governor valve member 285 moves upwardly,so that the lower spool portion 287 thereof again blocks the port 495.This cuts off the delivery of uid to the chamber 505 of the shift valveby way of the upper governor valve 285, but uid is still being deliveredto the chamber 514 from the rear pump via passage 518, since the car isstill in motion. Such fluid holds the shift control valve 506 up untilthe car slows down to a still lower speed. There is` thus a speed rangeunder such conditions wherein, although the governor has called for adownshift, the shift valve stays up and the car continues in the highgear. The lower end of the neck portion 508 of shift valve 506 carries ahead portion 509 of a larger diameter than the neck, and which isproportioned to accurately t and close the throat portion 515 when theshift valve is in the up position. Inasmuch as the spool 512 is biggerthan the head 509 at the lower end of the shift valve 506, this valve isbiased upwardly by rear pump pressure under such conditions, and thehead 509 closes communication between the chambers 514, 505, so thatrear pump pressure cannot be fed to the chamber 545 at the lower end ofthe lock-out clutch valve 546 via the passage 504, and passages 542,544, as previously described. Since the feed to the port 500 of thegovernor valve is also cut ott, the pressure is no longer maintained atthe lower end of the lock-out clutch valve, and the converter pressurewhich is applied to the chamber 672 at the upper end of the lock-outclutch valve moves the latter valve downwardlg.I permittingdisengagement of the lock-out clutch in the manner previously described.Under such conditions, the vehicle accordingly proceeds in high gear,but with the torque converter in the line of drive. lf the throttleshould be opened wider, the lower spool 537 of the lower governor valve288 would move up to open the port 522, relieving the pressure inchamber 514 and allowing the shift valve 506 to re-establish thestarting gear drive. Full depression of the accelerator also causes theports 498, 540 of the lower governor valve to be placed in communicationby the neck portion 536 of the valve, so that the lock-out clutch valve546 is again moved upwardly, but the lockout clutch will not engageuntil the accelerator is released to allow a torque reversal, so thatunder such conditions, accelerating from a low speed, both the torqueconverter and gearing are made available.

By way of example, it might be suitable to proportion the parts so thatthe governor would call for a downshitt, upon gradual deceleration ofthe vehicle, at about *.3 miles per hour. The rear pump biasing pressurein the chamber S14 would hold the shift valve 506 up. however. as thecar slowed down still further, below 13 miles per hour, although at thatspeed the hydraulic torque converter would be put back in the line ofdrive in the manner described. Assuming continuous light throttle, turHther slowing down of the vehicle, for example to aripron.4 mately 6miles per hour, would allow the rear pump pressure to fall slightly. Thespring 6i3 biasing the shift valve 506 downwardly is proportioned toovercome the rear pump biasing pressure at such a suitable desiredspeed, so that the valve 506 will move down and a downshift to thegeared ratio will then occur. After such a downshift, with the carproceeding in the geared ratio. th .f anticreep valve 360 and therelease vaivc 574 for the clutch 56 remain up and the actuating cylinder69 for the clutch 56 is vented, the passage 552 leading to the clutch 56being connected through ports 560 and 585 of the antlcreep valve,passage 626 and ports Stati and 626 of the clutch release valve 574 tothe passage lti. which then communicates via port 612 and past thereduced portion 614 of the valve 506 with the vent port 668. Analogousprovisions are made for venting each of the other actuating cylinderswhen the delivery of Huid there to is interrupted.

When the car is proceeding in high gear at a speed above the governordownshift speed (e. g. 1?' mites hour) and the throttle is opened wide(with the vehi speed slow enough, however, so that a kickdown ispossible), the pressure in chamber 514 of the shift valve 5F56 is dumpedat the port 522 of the lower `governor valve 288, and the pressure inthe shift valve chamber 505 is dumped by the upper governor valvethrough the port 502. However, the lock-out clutch valve is held up bythe connection of the ports 498, 540, connecting the pressure line 498with the chamber 545, which is ellected by the lower governor valve, andthe torque converter remains locked out of the line of drive. Immediategeared acceleration is thus available without the lag which is inherentin the slippage of the hydraulic torque converter.

lt will be noted also that a kickdown shift cannot occur if the speed otthe vehicle is so great that the upper governor valve cannot be movedupward by the spring 286 against the downward force exerted by theilyweights.

When the vehicle is at rest, or substantially at rest, the pressure inthe counterbiasing chambers 335. 337 of the pressure regulating valvesis zero or at a minimum. The pressure regulating valves thus tend tomaintain the maximum pressure in the hydraulic torque converter understarting conditions when the transmission of torque through suchconverter is at a maximum. The torque handled by the converter fallsaway rapidly as its turbine member comes up to speed, but when at highloads and substantial throttle openings greater torque demands areplaced upon the components of the transmission, the counterbias againfalls away, due to the opening of the variable orifice 52d, so thatrelatively high engagement pressures are applied to the clutch and brakemeans of the transmission. This will be seen to avoid the necessity ofmaintaining high pressures when not required by operating conditions,thereby considerably increasing the overall etllciency of thetransmission.

When the shift valve 506 drops, the fluid pressure is simultaneouslyrelieved in chamber 630 at the lower end of. the release valve 625 forthe forward speeds brake band 68 (line 618 being connected to vent 608by the dropping of shift valve 506). Valve 625 therefore moves down,cutting olf the supply line 490, which is then again vented throughpassage 635 and port 650 of the selector valve, so that band 68 isreapplied for the lower speed drive.

The pressure in the main fluid supply system varies substantially inaccordance with the torque demand, due to the control of thecounterbiasing action by variable orifice 524 as previously brought out.The converter valve 378 maintains a pressure differential between themain supply pressure and the pressure in the converter system andtherefore the pressure in the converter system also varies in accordancewith torque demand. This differential, as determined by the action ofthe valve 378, is set at about the value that is required to permit aclutch or brake which is to be engaged to effect an upshift to beapplied or engaged with sufficient force to take over the drive. lnshifting from low to second gear, the release valve 574 must be movedupwardly against converter pressure in the chamber 665, and in shiftingfrom second to high, the forward release valve 625 must be movedupwardly against converter pressure in the chamber 632. When the car hasbeen moving in low gear, the release valve 574 is down, since nopressure exists in the chamber 600 with the selector valve in the Lposition. Converter pressure is present in the upper chamber 605 of thevalve 574, so that when the selector valve is moved to the D" position,the shift to second gear cannot occur until the pressure in the chamber600 rises above the converter pressure. This insures that the clutch 56will not be released until there is enough pressure available in theline 439 and the actuating cylinder 67 for the clutch 55 to take overthe drive.

ln shifting from second gear to direct drive, clutch 56 must bere-engaged and brake band 68 must be released, fluid pressure beingrequired to perform both of these operations. Although in second gearthe release valve 574 for the clutch 56 is up, so that uid can passthrough this valve as soon as the shift control valve 506 drops, therelease valve 625 for the forward brake band 68 is down, and accordinglythe valve 625 cannot be moved upwardly until the pressure delivered tothe chamber 630 at its lower end rises above the converter pressure inits chamber 632, so that the valve will then move upwardly to allowpressure nid to move through the ports 642, 640 and via passage 490 tothe servomotor 450 for band 68, to release the band 68 only after thereis sufficient pressure to actuate clutch 56 to take over the drive.

ln reverse, the reverse interlock valve performs a timing function inthat it prevents delivery of lluid via line 704 to the actuatingcylinder 700 for the reverse drive brake band 36 until the pressurerises high enough in the passage system 490 leading to the releasecylinder 450 for the forward drive brake band 68 to release the latter.

l may also provide manual means for preventing engagement of thelock-out clutch in order that the flexibility and torque convertingelect of the hydraulic torque con- .verter may be maintained in the lineof drive at all times.

This is preferably Operated by a manual control such as a button on theinstrument panel (not shown) through the agency of which a blocking rod685 may be moved to u position to prevent upward movement of the valve546. 'lhe blocking member 685 is shown as comprising a rod slidableaxially through the upper casing portion of the valve 546 to and from aposition to hold such valve against upward movement.

When the selector valve is moved one position to the left, from theposition shown in Fig. 6, to the L" or lock-up emergency low position,the spool 435 moves to the left of the port 433 and the inlet port 365from the main iluid supply line 362 and then blocked, being isolatedbetween the spools 435, 436, The passage 635 is still connected to thevent port 650 by the reduced spool portion 645 of the selector valvewhich bridges the selector valve ports 644, 650. The anticreepconnection between the main line and the port 602 of anticreep valve 360is still effective by way of the conduit 550. Release valve 574 forclutch 56 cannot move up because there is no source of fluid supply forthe chamber 660 which constitutes the sole means for lifting the valve574. Chamber and the line 439 to the actuating means for clutch 55 arevented via passage 438 and the open right end of the casing of valve366.

The lluid from the main line 362 which by-passes the selector valve 366via the line 550 is conducted through the release valve 574 for clutch56, from the port 572 to port 580 past the neck 578 and into the passage626, from which it is led to the chamber 586 at the lower end of theanticreep valve 366` through passage 584. The pressure in chamber 586thus augments the upward force exerted on the spool 588 by the portionof such bypassed fluid which is led directly to the port 602 of theanticreep valve, and the parts are so proportioned that the total upwardforce on the anticreep valve under such conditions is sufficient toraise the valve against the effort of the spring 555, even when thevehicle is stationary (rear pump not operating). Therefore, with theselector valve in the L setting, the anticreep valve rises to block theport 602 and uncover the port 585, establishing a full pressure iluidconductive connection through the anticreep valve from the port 58S pastthe neck 556 of the outlet port 560. lt will be seen that the only brakeand clutch means engaged under these conditions comprise a brake banl;68 and the clutch 56. This is the condition required for low gearoperation, and under such conditions, low gear remains eltective untilthe position of the selector valve is changed.

When the selector valve is moved all the way to the left to the reverseposition, marked R, the spool 436 moves to the left of the port 644,while the spool 435 is still to the right of the inlet port 365 andcommunication is established between the inlet port 365 from the mainline and outlet port 644 past neck 434. Valve 625 is then in the downposition, and fluid is delivered to the release cylin der 450 for theforward speed brake band 68 by way of passage 635, ports 642, 640,passage 490, etc. as previously described, to release the forward speedsbrake band 68. Fluid is also delivered through a port 690 and a passage692 to a chamber 694 at the lower end of a reverse interlock valve 636.Such pressure moves the valve 636 upwardly against the resistance of itsbiasing spring 695, closing the vent port 696 for the reverse brake bandactuating cylinder 700, which is connected by line 704 to an outlet port702 of the valve 636 located at a point between the chamber 694 and Ventport 696. Fluid then passes under the lower spool 703 of valve 636 toport 702. Port 702 is connected to the cylinder 700 by a passage systemgenerally designated 704. At the upper end of the valve 636 is a chamber705 which contains the spring 695 and which is connected throughpassageways 706. fitlt'l and 405 to the rear pump output line 314. Whenthe rear pump 240 is rotating backwards because the car is movingrearwardly, this pump generates no pressure, but when the ear is movingforwardly, rear pump pressure in chamber 705 keeps the valve 636 frommoving upwardly', an.g the reverse brake bank 36 accordingly cannot beengaged. This eliminates the danger of throwing car into reversa: whenmoving forwardly. Pressure is at the same time delivered to theactuating cylinder' for the clutch 56 through the ports 572, :380 of therelease valve 574 for the clutch 56, and through ports 585, 560 of theanticreep valve as in the lov.I geitr operation previously described.The parts are thus conditioned for reverse operation.

When the selector valve 366 is moved one notch to the right from theposition shown in Fig. 6, to the neutral position designated N, the mainuid supply line is connected to the conduit 490 which supplies therelease cylinder 450 for the broke band 68, and fluid is also suppliedto the actuating cylinder for the clutch 56 by way of the passages 368,558. valves 574-360, etc., as just described in connection with thereverse drive arrangement. Connection to the passage 490 is through theportion of the chamber of selector valve 366 surrounding the neck 645and through the angular valve passage 648 which connects such chamber tothe port 644, and via passage 635 and ports 642, 640 of forward brakerelease valve 625. The other ports of the selector valve 366 areisolated from the inlet port 365 by the spools 436, 646. Thus inneutral, with the engine running, clutch 56 is engaged and the otherclutches and brakes are disengaged.

When the selector valve is moved one position farther to the right. tothe park position designated P in Fig. 6, the inlet port 365 to theselector valve is completely blocked. Fluid is still supplied to theline 552 to engage the clutch 56 and the band 68 is also engaged, sinceno fluid is being supplied to the line 490. (Line 490 is vented throughport 644 and past neck portion 647 of the .selector valve 366 to ventport 650.) Movement of the selector valve 366 to the park position alsourges the locking dog 200 in a direction to cause a tooth 710 carried bysuch dog to enter one of the holes 198 formed in appropriate position inthe periphery of the drum 35. The dog 200 is actuated by an arm 714pivoted upon a xed pin 715 in the transmission case, and so connected tothe actuating hand lever for the selector valve that it is rockedinwardly toward the drum when the hand lever is moved to the parkposition, simultaneously with movement of the selector valve to suchposition. The arm 714 does not act directly upon the dog 200 in aninward or latching direction, but urges it inwardly toward the drum 35through the agency of a compression spring 716 trapped between the armand the dog, as shown in Fig. 6. Thus if the tooth 710 is not inalignment with one of the holes 198, it is urged inwardly against thedrum and enters one of such holcs as soon as the drum rotates suicientlyto permit it. When the hand lever is moved away from the park positionit moves the arm 714 outwardly to cause the arm to engage a lug 712carried by the latch piece 200 and pull the latch piece free of thedrum. Another lug 718 on the dog 200 serves as an abutment for thespring 716, and also as an abutment engageable by an interlock plunger720 slidable to and from a blocking position, in which it is shown inFig. 6, in which it positively holds the dog 200 away from the drum 35,so that the tooth 710 clears the drum and cannot prevent rotation of thelatter.

- by the spring 474.

The plunger 720 is biased away from such blocking position by a spring722, but is moved into and held in the blocking position Whenever therear pump is generating pressure. An actuating piston portion 724, shownas formed integrally upon the lower end of the plunger 720, is connectedto the passage 404, leading to the rear pump output, by passages 725,726. The plunger 720 is also movable upward to the blocking position bya plunger 728, which is separate from the piston portion 724, butslidable in a coaxial downward extension of the cylindrical chamber 730in which the piston 724 is slidable. The passage 725 is connected to aport 732 which enters chamber 730 between the piston 724 and plunger728. The cylinder portion 730 below the plunger 728 is connected by apassage 734 to the passage system 490 leading to the recylinder 450 forthe forward speeds brake band 68. Delivery of uid to the release meansfor the brake band 68 thus also acts to hold the plunger 720 in theblocking position in which it prevents engagement of the parking latch.

Whenever the hand lever is shifted to the park position from anyposition (neutral, third or reverse) wherein the brake band 68 has beenreleased, the engagement of the brake band 68 is required, and thisentails downward movement of the piston 480 (Fig. 5) and displacement ofuid from the cylinder 450 via thc conduit 490. Such uid is conductedthrough the branch passage 734 to the cylinder 730 below the interlockvalve piston 728. The fluid pressure thus applied to the interlockmember 720 holds the latch piece 200 away from the drum 3S, until thedrurn has been stopped by the action of band 68.

Whenever the car is moving forwardly, the drum 35 will be turning andthe rear pump will be delivering uid pressure directly to the chamberbeneath the upper interlock valve piston 724 via passages 314, 405, 404,'726 and 725. The latch piece 200 is thus held away from the drum in apositive manner which prevents clashing or damage due to an attempt toengage the parking dog while the car is moving forwardly. When the caris moving rearwardly under its own power, the drum 35 is held by theband 36, so that engagement of the parking latch at such time does noharm, merely bringing the car to a standstill as the brake band 68engages the drum 66.

In the park position, the brake band 68 is held engaged If a force isexerted tending to roll the car, the carrier 44 is held against movementand so the car cannot roll, since the rear sun gear 45 is held by theband 68, while the internal toothed gear 42 of the rear set is held bythe parking latch tooth 710 which locks the drum 35. The rear planetgear and carrier, and driven shaft 30, and 20 the rear wheels, are thusheld immovable. When the engine is running with the parts in such parksetting, the clutch 56 is also engaged. Thus the front gearset is alsolocked up, and slip occurs in the hydraulic torque converter, and theplanet gears cannot se rotated at excessive speeds by speeding up theengine, because of the drag of the torque converter.

A detail of the actuating means for the clutches 55 and 56 which has notpreviously been mentioned, and which is shown in Fig. 1B, comprisesmeans for preventing fluid trapped in the cylinders 67 and 6! fromapplying these clutches under the influence of centrifugal force. Nearits periphery the piston assembly 62 is provided with an axial aperture802 in which is loosely fited n stem 804. The aperture and stem may beof different cross-sectional shape to permit the passage of lluitl pastthe stem. For example, the stern may be round and the hole square. Thestern carries a valve head portion 88.3 which. is located between thepiston 62 and the laterally offset annuiar outer portion 5,06 of thepressure plate 216. The annular pocket defined by the otlset portion 806also contains a leaf spring 808 which bears inwardly against the valvehead 805 and normally urges such valve head against the outer end of thehole 802. The stern 804 is long enough so that when the piston isretracted against the partition 54, as shown in Fig. 1B, which is theposition it occupies when the clutch 55 is released, the head 805 isheld away from the piston and the hole 802 provides communicationbetween the cylinder space 67 and the annular chamber defined by theoffset portion 806 of the pressure plate 216. When the `piston moves tothe left far enough to engage the clutch 55, the underside of the valvehead 805 engages the piston as the stern 804 moves free of the partition54, so that the valve then closes the opening 802. The spring 808 isstrong enough so that it cannot be opened by the actuating pressureapplied to the piston. Peripheral openings are formed in the pressureplate to allow any uid which passes out through the hole 802 to escapeinto the transmission case. The peripheral openings in the pressureplate are shown in the form of notches 810, By virtue of thisarrangement, any fluid in the cylinder and/or in the chamber between thepressure plate and the piston can escape through the holes 802 and 810and cannot cause unwanted engagement of the clutch. The effectivecross-sectional area of the passage provided between the stem 804 andthe wall of hole 802 is small, however, with relation to the volume oftiuid delivered to the cylinder when actuation of the clutch isinstituted by its operating mechanism previously described, so thecontrolled bleeding arrangement past the valve stern 804 cannot preventnormal and intended operation of the piston. A similar arrangement isprovided for permitting escape of uid trapped in the cylinder 69 behindthe actuating piston 65 for the clutch 56. The valve for this purpose isgenerally designated 812, and detailed description of the means forcontrolling the escape of uid from the cylinder 65 will not be requiredsince the parts are substantially the same as those for cylinder 67.

Although the preferred embodiment of the invention herein disclosed iswell calculated to fulll the objects and advantages previously stated,it is to be understood that various modifications may be made withoutdeparting from the spirit and scope of the subjoined claims.

What is claimed is:

l. In a transmission, two substantially coaxial mechanicallyinterconnected planetary gear-sets, each gearset including a pluralityof rotatable elements, and a clutch substantially circumferentiallysurrounding one of said gearsets and having a plurality of rotatableclutchable elements, one of said clutchable elements being independentof the surrounded gearset and connected to one of the rotatable elementsof the other gearset and another of the clutchable elements beingconnected to another rotatable element of said other gearset, saidclutchable elements being operable to lock-up said other gearset.

7.. In an automatic transmission system having an input shaft and anoutput shaft and including hydraulically operable components, a pair ofpumps for supplying hydraulic iluid, one pump being operable by theinput shaft and the other by the output shaft, a dump valve for ventingone of said pumps, means responsive to the pressure developed by theother pump for opening said valve, means defining a bleed openingconnected to said other pump, and means responsive to actuation of thedump valve for closing said bleed opening.

3. In an automatic transmission system having hydraulically operablecomponents, two uid pressure generating devices, a common supply portionconnecting said two devices to said components, means limitingtransmission of back pressure to either of said devices from the other,means for rendering one of said devices inoperative, pressure responsivemeans for actuating said lastnamed means, said pressure responsive meansbeing connected to and responsive to the pressure developed by the otherof said devices, means defining a substantially fixed escape passageconnected to said Other of said devices, and means responsive to theoutput of said other of said devices for closing said escape passage.

4. In an automatic transmission system including an input shaft and anoutput shaft and having hydraulically operable control components, a rstpump operable by the input shaft, a second pump operable by the outputshaft. means for delivering Huid from both pumps to said componentsincluding a common delivery passage, a pair of check valves, one checkvalve interposed between the output of each pump and said passage, adump valve connected to the rst pump between such output and the checkvalve, an actuator for the dump valve connected to the output of thesecond pump between such pump and the check valve and operative toactuate such dump valve to dump the rst pump when the output of thesecond pump reaches a predetermined pressure, a metering dischargeportion also connected to the output of the second pump, and means forclosing such discharge portion concurrently with actuation of the dumpvalve.

5. In a transmission construction in combination with gearing includinga planetary gear set having concentrically disposed sun gear, planetgear and ring gear members, and a planet carrier, shafting supportingthe sun gear member from one side of said gear set and supporting thering gear member from the other side of said gear set, a case supportingthe shafting, a reaction brake including a drum connected to the carrierand extending radially outwardly on one side of said gear set and thencelaterally around the ring gear member and projecting axially from theother side of the gear set concentrically with respect to the shafting,a drum support rotatable with the drum and extending inwardly therefromon the opposite side of the gear set and having its radially innermostportion journaled on the casing independently of and to the side of thegearing, and braking means engageable with the drum in substantialcircumferential alignment with the drum support.

6. In a transmission construction in combination with planetary gearing,shafting supporting the gearing and a case supporting the shafting, areaction brake including a drum connected to a part of the gearing andextending laterally therefrom in a direction axially ot' and concentricwith the shafting, a drum support journaled on the casing independentlyand to one side of the gearing, and braking means engageable with thedrum in substantial alignment with the drum support, the drum beingkeyed to rotate with the bearing but axially movable with relationthereto.

7. In a transmission construction in combination with planetary gearing,shafting supporting the gearing and a case supporting the shafting, areaction brake including a drum connected to a part of the gearing andextending laterally therefrom in a direction axially of and concentricwith the shafting, a drum support journaled on the casing independentlyand to one side of the gearing, and braking means engageable with thedrum in substantial alignment with the drum sup-port, the drum beingkeyed to rotate with the gearing but axially movable with relationthereto, the drum support and drum being secured to one another againstrelative axial movement and the drum support being held against unwantedaxial movement with relation to the case.

8. In a transmission, two substantially coaxial planetary gear sets,each gear set including a sun gear, a planet carrier, planet gearsmounted in the carrier, and a ring gear meshing with the planet gears,the carrier of a first one of said gear sets being rotatable with thering gear or' a second one of said gear sets, means for transmitting adrive to the ring gear of the first gear set and means for taking adrive from the carrier of the second gear set, and a lockup clutch forlocking up the first gear set including a clutching element mounted onand supported by and fast with respect to the ring gear of the secondgear set, and a second clutch element with which the first clutchelement is selectively engageable, said second clutch 27 element beingrotatable independently of the second gear set and connected to the sungear of the rst gear set.

9. In a transmission, two substantially coaxial planetary gear sets,each gear set including a sun gear, a planet carrier, planet gearsmounted in the carrier, and a ring gear meshing with the planet gears,the carrier of a first one of said gear sets being rotatable with thering gear of a second one of said gear sets, means for transmitting adrive to the ring gear of the first gear set and means for taking adrive from the carrier of the sti: nd gear set, and a locltup clutch forlocking up the first geur ser including a clutching element keyed uponand surrounding and rotatable with the ring gear of the second gear setin substantially coplanar relation therewith, and a second clutchelement with which the rst clutch element is selectively engageable,said second clutch element being rotatable independently of the secondgear set and connected to the sun gear of the first gear set, both ofsaid clutch elements being located in a position surrounding said ringgear of the second gear set.

l0. In a transmission construction, in combination with a case,planetary gearing in the case having a plurality of gear elements, asupporting shaft for one of the gear elements carried by and extendingfreely inwardly a substantial distance from a wall of the case andcarrying said gear element fast thereupon at a point spaced from thecase, thereby permitting limited radial floating movement of such gearelement, a bearing support for such shaft carried by the case, suchsupport also extending inwardly toward said supported gear clement butterminating at a point spaced from such gear element, means forcontrolling rotation of such gear element and shaft including a brakedrum secured to said shaft and overhanging said bearing support, brakingmeans engageable with said overhanging portion of the brake drum,clutching means for controlling another element of said planetarygearing including a clutching element surrounding said gearing, andsupportmcans for said clutching element including a part rotatablysupported upon said shaft between said rst mentioned supported gearelement and said brake drum, said clutching means being Huid actuatable,and iluid conducting means for said clutching means extending throughsaid shaft.

l l. in a transmission construction, a pair of planetary gear setsserially arranged, each gear set including a sun gear. a carrier, aplanetary gear and a ring gear, the carrier of a first one of said gearsets being connected to the ring gear of the second of said gear sets, aclutch casing rotatably connected to the sun gear of the first gear setand rotatable independently of the second gear set, two clutches in saidcasing, one of said clutches being engageable to connect the casing andthe sun gear of the lirst gear set to the ring gear ofthe second gearset and the other clutch being engageable and disengageable to make andbreak a driving connection between said casing and the sun gear of thesecond gear set.

l2. In a transmission construction, a pair of planetary gezusctsserially arranged, each gear set including a sun gear, u. carrier, aplanetary gear and a ring gear, the carrier ot' a first one of said gearsets being connected tothe ring gear of the second of said gear sets, aclutch casing rotatably' connected to the sun gear of the lirst gear setand rotatable independently of the second gear set, two clutches in saidcasing, one of said clutches being engageable to connect the casing andthe sun gear of the first gear set to the ring gear of the second gearset, and the othei` clutch being engageable and disengageable to makeand break a driving connection between said casing and the sun gear ofthe second gear set, and braking means for holding the sun gear of thesecond gear set against unwanted rotation without interfering withrotation of said casing.

i3. In a transmission construction, a pair of planetary gear setsserially arranged, each gear set including a sun gear, a carrier, aplanetary gear and a ring gear, the carrier of a rst one of said gearsets being connected to the ring gear of the second of said gear sets, aclutch casing ro tatably connected to the sun gear of the first gear setand rotatable independently of the second gear set, two clutches in saidcasing, one of said clutches being engageable to connect the casing andthe sun gear of the first gear set to the ring gear of the second gearset, and the other clutch being engageable and disengageable to make andbreak a driving connection between said casing and the sun gear of thesecond gear set, two separate braking means, one of said braking meansbeing independent of said casing and engageable to hold the sun gear ofthe second gear set against undesired rotation and the other of saidbraking means being engageable to hold the carrier of the first gear setag; nst unwanted rotation.

14. In an automatic transmission system incorporating torquetransmitting components the operation of which depends on the provisionand maintenance of hydrostatic pressure, said system being adapted forinstallation in a vehicle having a driving engine and a throttle controlfor the engine, means for supplying iluid under pressure for theoperation of such components, movable pressure varying means connectedto said throttle control and arranged to proportionately urge saidpressure varying means in a direction to decrease the effective pressureas the throttle is moved from the open position toward the closedposition, and vice-versa, and means responsive to movement of thevehicle to urge said pressure varying means in a direction to reduce thepressure output in proportion to increasing speed of the vehicle, andviceversa.

l5. In an automatic transmission system incorporating torquetransmitting components the operation of which depends on the provisionand maintenance of hydrostatic pressure, said system being adapted forinstallation in a vehicle having a driving engine, means for supplyingfluid under pressure for the operation of such components, regulatingmeans movable to vary the effective output pressure from said supplyingmeans, and means responsive to movement of the vehicle to urge theregulating means in a direction to reduce the effective output pressurefrom said supply means proportionately with increasing speed of thevehicle, and vice-versa, and restricting means opposing movement of saidregulating means at low vehicle speeds and in response to relativelyslight variations of vehicle speed.

16. In an automatic transmission system incorporating torquetransmitting elements the operation of which depends on the provisionand maintenance of hydrostatic pressure, said system being adapted forinstallation in a vehicle having a driving engine and a throttle controlfor the engine, two pressure generating means, one operable by theengine and the other operable in response to movement of the vehicle, apressure regulating valve movable to vary the effective pressurederivable from the output of the first mentioned generating means, apressure regulating valve movable to vary the effective pressurederivable from the output of the second generating means, and meansresponsive to movement of said throttle control to simultaneouslyinfluence both of said regulating valves to impose a variable increasein the effective output pressure of both of said generating means inresponse to the opening of said throttle control.

17. A transmission adapted for installation in a motor vehicle having aspeed controller and incorporating a hydraulic torque conveyor and aratio changing device actuatable by hydrostatic pressure and movable toengaged and disengaged conditions and coacting with the torque conveyor,hydraulic actuating means for said device, hydrostatic fluid pressuregenerating means responsive to movement of the vehicle, means responsiveto actuation of said controller for varying the hydrostatic pressurederived from said generating means and delivered to said torqueconveyor, and means in Huid conductive communication with the torqueconveyor and connected to said hydraulic

